Apparatus and method for processing substrate

ABSTRACT

The inventive concept relates to an apparatus for processing a substrate. In an embodiment, the apparatus includes a process chamber having a processing space inside, a support unit that supports the substrate in the processing space, a gas supply unit that supplies a process gas into the processing space, and a plasma source that generates plasma from the process gas. The support unit includes a support on which the substrate is placed, an edge ring around the substrate placed on the support, an impedance adjustment member provided below the edge ring, and a temperature adjustment member that variably adjusts temperature of the impedance adjustment member.

CROSS-REFERENCE TO RELATED APPLICATIONS

A claim for priority under 35 U.S.C. § 119 is made to Korean PatentApplication No. 10-2018-0038142 filed on Apr. 2, 2018, in the KoreanIntellectual Property Office, the entire contents of which are herebyincorporated by reference.

BACKGROUND

Embodiments of the inventive concept described herein relate to anapparatus for processing a substrate, and more particularly, relate toan apparatus for processing a substrate using plasma.

Plasma may be used to process a substrate. For example, plasma may beused in an etching, deposition, or dry cleaning process. Plasma isgenerated by heating or subjecting a neutral gas to a strong electricfield or a radio frequency (RF) electromagnetic field and refers to anionized gaseous state of matter containing ions, electrons, andradicals. A dry cleaning, ashing, or etching process using plasma isperformed by allowing ions or radical particles contained in the plasmato collide with a substrate.

A substrate processing apparatus using plasma may include a chamber, asubstrate support unit, and a plasma source. The substrate support unitmay include an edge ring disposed to surround a substrate. The edge ringmay be worn by plasma. The worn edge ring may cause non-uniformdistribution of plasma incident on the substrate. The non-uniform plasmadistribution may produce a result that the substrate is not processeduniformly.

SUMMARY

Embodiments of the inventive concept provide a substrate processingapparatus and method for improving processing efficiency in processing asubstrate using plasma.

Embodiments of the inventive concept provide a substrate processingapparatus for uniformly controlling distribution of plasma incident on asubstrate.

According to an exemplary embodiment, an apparatus for processing asubstrate includes a process chamber having a processing space inside, asupport unit that supports the substrate in the processing space, a gassupply unit that supplies a process gas into the processing space, and aplasma source that generates plasma from the process gas. The supportunit includes a support on which the substrate is placed, an edge ringthat surrounds the substrate placed on the support, an impedanceadjustment member provided below the edge ring, and a temperatureadjustment member that variably adjusts temperature of the impedanceadjustment member.

The impedance adjustment member may be made of a material, thedielectric constant of which varies according to temperature.

The apparatus may further include a controller that controls thetemperature adjustment member. The controller may control thetemperature adjustment member to change the dielectric constant of theimpedance adjustment member as a amount of corrosion of the edge ringincreases.

The controller may control the temperature adjustment member to increasethe dielectric constant of the impedance adjustment member as the amountof corrosion of the edge ring increases.

The apparatus may further include a corrosion measurement member thatmeasures the amount of corrosion of the edge ring. The controller mayreceive the amount of corrosion measured by the corrosion measurementmember.

The impedance adjustment member may be formed of a dielectric substancecontaining magnesium oxide.

The dielectric substance may contain 10 wt % to 50 wt % of magnesiumoxide.

The apparatus may further include a controller that controls thetemperature adjustment member. The controller may control temperature ofthe temperature adjustment member, based on a amount of corrosion of theedge ring.

The impedance adjustment member may have the highest dielectric constantat a first temperature, an increasing dielectric constant with atemperature rise in a range below the first temperature, and adecreasing dielectric constant with a temperature rise in a range abovethe first temperature. The controller may control the temperatureadjustment member to raise the temperature of the impedance adjustmentmember in the range below the first temperature and lower thetemperature of the impedance adjustment member in the range above thefirst temperature, when a amount of corrosion of the edge ringincreases.

The impedance adjustment member may have a ring shape with an uppersurface that corresponds to a shape of a lower portion of the edge ring.

According to an exemplary embodiment, a method for processing asubstrate includes processing the substrate by supplying plasma onto thesubstrate placed on a support and controlling a plasma density above anedge ring by adjusting a dielectric constant of an impedance adjustmentmember that is placed below the edge ring that surrounds a side of thesubstrate placed on the support.

The method may further include variably adjusting the dielectricconstant of the impedance adjustment member, based on a amount ofcorrosion of the edge ring.

The impedance adjustment member may be formed of a dielectric substancecontaining magnesium oxide.

The dielectric substance may contain 10 wt % to 50 wt % of magnesiumoxide.

The method may further include controlling temperature to increase thedielectric constant of the impedance adjustment member as a amount ofcorrosion of the edge ring increases.

The impedance adjustment member may have the highest dielectric constantat a first temperature, an increasing dielectric constant with atemperature rise in a range below the first temperature, and adecreasing dielectric constant with a temperature rise in a range abovethe first temperature. Temperature of the impedance adjustment membermay be raised in the range below the first temperature and lowered inthe range above the first temperature when a amount of corrosion of theedge ring increases.

The method may further include measuring a amount of corrosion of theedge ring and changing the dielectric constant of the impedanceadjustment member according to the measured amount of corrosion.

The method may further include changing the dielectric constant of theimpedance adjustment member according to cumulative substrate processingtime.

The method may further include changing the dielectric constant of theimpedance adjustment member according to the number of substratesprocessed.

BRIEF DESCRIPTION OF THE FIGURES

The above and other objects and features will become apparent from thefollowing description with reference to the following figures, whereinlike reference numerals refer to like parts throughout the variousfigures unless otherwise specified, and wherein:

FIG. 1 is a sectional view illustrating a substrate processing apparatusaccording to an embodiment of the inventive concept;

FIGS. 2 and 3 are enlarged views illustrating corrosion states caused byuse of an edge ring according to an embodiment of the inventive concept;

FIGS. 4 and 5 are enlarged views illustrating the behavior of plasmanear the edge ring of a support unit according to an embodiment of theinventive concept;

FIG. 6 is a graph of dielectric constant versus temperature fordielectric substances according to an embodiment of the inventiveconcept; and

FIG. 7 is a graph of dielectric constant versus temperature for a fourthdielectric substance according to an embodiment of the inventiveconcept.

DETAILED DESCRIPTION

Hereinafter, embodiments of the inventive concept will be described inmore detail with reference to the accompanying drawings. The inventiveconcept may, however, be embodied in different forms and should not beconstructed as limited to the embodiments set forth herein. Rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the inventive conceptto those skilled in the art. In the drawings, the dimensions ofcomponents are exaggerated for clarity of illustration.

A substrate processing apparatus for causing a substrate to be worn byplasma will be described in an embodiment of the inventive concept.Without being limited thereto, however, the inventive concept isapplicable to various types of apparatuses for performing a process bysupplying plasma into a chamber.

FIG. 1 is a sectional view illustrating a substrate processing apparatus10 according to an embodiment of the inventive concept.

Referring to FIG. 1, the substrate processing apparatus 10 processes asubstrate W using plasma. For example, the substrate processingapparatus 10 may perform a etching process on the substrate W. Thesubstrate processing apparatus 10 includes a chamber 100, a support unit200, a gas supply unit 300, a plasma source 400, and an exhaust baffle500.

The chamber 100 has a space in which substrate processing is performed.The chamber 100 includes a housing 110, a dielectric cover 120, and aliner 130.

The housing 110 is open at the top and has a processing space therein.The processing space is a space in which substrate processing isperformed. The housing 110 is made of metal. The housing 110 may be madeof aluminum. The housing 110 may be grounded.

The housing 110 has an exhaust hole 102 formed in the bottom thereof.The exhaust hole 102 is connected with an exhaust line 151. Reactionbyproducts generated during processing and gases staying in the innerspace of the housing 110 may be discharged to the outside through theexhaust line 151. The pressure inside the housing 110 is reduced to apredetermined pressure by the exhaust process.

The dielectric cover 120 covers the open top of the housing 110. Thedielectric cover 120 has a plate shape and seals the inner space of thehousing 110. The dielectric cover 120 may be provided so as to beremovable. According to an embodiment of the inventive concept, a flowpassage 611 is formed in the dielectric cover 120. Furthermore, thedielectric cover 120 may include a plurality of dielectric plates.

The liner 130 is provided inside the housing 110. The liner 130 has aspace formed therein, which is open at the top and the bottom. The liner130 may have a cylindrical shape. The liner 130 may have a radiuscorresponding to an inner surface of the housing 110. The liner 130 isprovided along the inner surface of the housing 110. A support ring 131is formed at the top of the liner 130. The support ring 131 isimplemented with a plate in a ring shape and protrudes outside the liner130 along the periphery of the liner 130. The support ring 131 is placedon an upper end of the housing 110 and supports the liner 130. The liner130 may be made of the same material as that of the housing 110. Theliner 130 may be made of aluminum. The liner 130 protects the innersurface of the housing 110.

The support unit 200 is located in the processing space of the chamber100. The support unit 200 supports the substrate W. The support unit 200may include an electrostatic chuck that electro-statically clamps thesubstrate W using electrostatic force. Alternatively, the support unit200 may support the substrate W by various methods such as mechanicalclamping. Hereinafter, the support unit 200 including the electrostaticchuck will be described.

The support unit 200 includes the electrostatic chuck, an insulatingplate 250, and a lower cover 270. The support unit 200 is located in thechamber 100 and is spaced apart upward from the bottom of the housing110.

The electrostatic chuck includes a dielectric plate 220, a chuckingelectrode 223, a heater 225, a support plate 230, an edge ring 240, andan impedance adjustment member 245. The present embodiment is describedin which the electrostatic chuck includes the edge ring 240 and theimpedance adjusting member 245. However, the edge ring 240 and theimpedance adjusting member 245 may be separated from the electrostaticchuck.

The dielectric plate 220 is located at the top of the electrostaticchuck. The dielectric plate 220 is formed of a dielectric substance in adisk shape. The substrate W is placed on the top side of the dielectricplate 220.

The dielectric plate 220 has first supply passages 221 formed therein.The first supply passages 221 extend from the top side to the bottomside of the dielectric plate. The first supply passages 221 are spacedapart from each other and serve as passages through which a heattransfer medium is supplied to the bottom side of the substrate W.

The chucking electrode 223 and the heater 225 are buried in thedielectric plate 220. The chucking electrode 223 is located above theheater 225. The chucking electrode 223 is electrically connected to afirst lower power supply 223 a. The first lower power supply 223 aincludes a direct current (DC) power supply.

A switch 223 b is installed between the chucking electrode 223 and thefirst lower power supply 223 a. The chucking electrode 223 may beelectrically connected to, or disconnected from, the first lower powersupply 223 a by turning on/off the switch 223 b. When the switch 223 bis turned on, DC current is applied to the chucking electrode 223. Thecurrent applied to the chucking electrode 223 induces electrostaticforce between the chucking electrode 223 and the substrate W, and thesubstrate W is clamped to the dielectric plate 220 by the electrostaticforce.

The heater 225 is electrically connected to a second lower power supply225 a. The heater 225 generates heat by resisting current applied by thesecond lower power supply 225 a. The generated heat is transferred tothe substrate W through the dielectric plate 220. The substrate W ismaintained at a predetermined temperature by the heat generated from theheater 225. The heater 225 includes a spiral coil.

The support plate 230 is located below the dielectric plate 220. Thebottom side of the dielectric plate 220 and the top side of the supportplate 230 may be bonded by an adhesive 236. The support plate 230 may bemade of aluminum. The top side of the support plate 230 may have a stepsuch that the central region of the top side is located in a higherposition than the edge region of the top side. The central region of thetop side of the support plate 230 has an area corresponding to thebottom side of the dielectric plate 220 and is bonded to the bottom sideof the dielectric plate 220. The support plate 230 has a firstcirculation passage 231, a second circulation passage 232, and secondsupply passages 233 formed therein.

The first circulation passage 231 serves as a passage through which theheat transfer medium circulates. The first circulation passage 231 maybe formed in a spiral shape in the support plate 230. Alternatively, thefirst circulation passage 231 may include a plurality of concentricannular passages having different radii. The first circulation passages231 may be connected together. The first circulation passages 231 areformed at the same height.

The second circulation passage 232 serves as a passage through whichcooling fluid circulates. The second circulation passage 232 may beformed in a spiral shape in the support plate 230. Alternatively, thesecond circulation passage 232 may include a plurality of concentricannular passages having different radii. The second circulation passages232 may be connected together. The second circulation passages 232 mayhave a larger cross-sectional area than the first circulation passages231. The second circulation passages 232 are formed at the same height.The second circulation passages 232 may be located below the firstcirculation passages 231.

The second supply passages 233 extend upward from the first circulationpassages 231 to the top side of the support plate 230. As many secondsupply passages 233 as the first supply passages 221 are formed. Thesecond supply passages 233 connect the first circulation passages 231and the first supply passages 221.

The first circulation passages 231 are connected to heat transfer mediumstorage 231 a through a heat transfer medium supply line 231 b. The heattransfer medium storage 231 a has a heat transfer medium stored therein.The heat transfer medium includes an inert gas. According to anembodiment, the heat transfer medium includes helium (He) gas. Thehelium gas is supplied to the first circulation passages 231 through theheat transfer medium supply line 231 b and then supplied to the bottomside of the substrate W via the second supply passages 233 and the firstsupply passages 221 in a serial order. The helium gas serves as a mediumthrough which heat transferred from plasma to the substrate W istransferred to the electrostatic chuck.

The second circulation passages 232 are connected to cooling fluidstorage 232 a through a cooling fluid supply line 232 c. The coolingfluid storage 232 a has cooling fluid stored therein. The cooling fluidstorage 232 a may include a cooler 232 b therein. The cooler 232 b coolsthe cooling fluid to a predetermined temperature. Alternatively, thecooler 232 b may be mounted on the cooling fluid supply line 232 c. Thecooling fluid supplied to the second circulation passages 232 throughthe cooling fluid supply line 232 c cools the support plate 230 whilecirculating through the second circulation passages 232. The supportplate 230, while being cooled, cools the dielectric plate 220 and thesubstrate W together to maintain the substrate W at a predeterminedtemperature.

The edge ring 240 is disposed at the edge of the electrostatic chuck.The edge ring 240 has a ring shape and is disposed around the dielectricplate 220. The top side of the edge ring 240 may have a step such thatan outer portion 240 a of the top side is located in a higher positionthan an inner portion 240 b of the top side. The inner portion 240 b ofthe top side of the edge ring 240 is flush with the top side of thedielectric plate 220.

The edge ring 240 surrounds the edge of the substrate W located on thetop side of the dielectric plate 220. The edge ring 240 allows plasma inthe chamber 100 to be concentrated on a region that faces the substrateW.

The impedance adjustment member 245 is disposed below the edge ring 240.The impedance adjustment member 245 has a ring shape, the top side ofwhich corresponds to the shape of the bottom of the edge ring 240. Theimpedance adjustment member 245 is formed of a dielectric substance, thedielectric constant of which varies according to temperature. Theimpedance adjustment member 245 is made of a material that has a largevariation in dielectric constant according to a temperature change.

A temperature adjustment member 247 is mounted on the impedanceadjustment member 245. The temperature adjustment member 247 isconnected to a controller 600. The temperature adjustment member 247adjusts the temperature of the impedance adjustment member 245 to varythe dielectric constant thereof, thereby adjusting impedance.

The insulating plate 250 is located below the support plate 230. Theinsulating plate 250 has a cross-sectional area corresponding to that ofthe support plate 230. The insulating plate 250 is located between thesupport plate 230 and the lower cover 270. The insulating plate 250 ismade of an insulating material and electrically insulates the supportplate 230 from the lower cover 270.

The lower cover 270 is located at the bottom of the support unit 200.The lower cover 270 is spaced apart upward from the bottom of thehousing 110. The lower cover 270 has a space formed therein, which isopen at the top. The top side of the lower cover 270 is covered with theinsulating plate 250. Accordingly, the outer diameter of thecross-section of the lower cover 270 may be the same as the outerdiameter of the insulating plate 250. The lower cover 270 has an innerspace in which to accommodate a lift pin module (not illustrated) thatmoves the transferred substrate W from an external transfer member tothe electrostatic chuck.

The lower cover 270 has connecting members 273. The connecting members273 connect the outer surface of the lower cover 270 and the inner wallof the housing 110. The connecting members 273 may be provided on theouter surface of the lower cover 270 at predetermined intervals. Theconnecting members 273 support the support unit 200 inside the chamber100. Furthermore, the connecting members 273 are connected to the innerwall of the housing 110 to allow the lower cover 270 to be electricallygrounded. A first power line 223 c connected to the first lower powersupply 223 a, a second power line 225 c connected to the second lowerpower supply 225 a, the heat transfer medium supply line 231 b connectedto the heat transfer medium storage 231 a, and the cooling fluid supplyline 232 c connected to the cooling fluid storage 232 a extend into thelower cover 270 through inner spaces of the connecting members 273.

The gas supply unit 300 supplies a process gas into the processing spaceof the chamber 100. The gas supply unit 300 includes a gas supply nozzle310, a gas supply line 320, and gas storage 330. The gas supply nozzle310 is inserted through the central portion of the dielectric cover 120.The gas supply nozzle 310 has an injection hole formed in the bottomthereof. The injection hole is located below the dielectric cover 120and supplies the process gas into the processing space of the chamber100. The gas supply line 320 connects the gas supply nozzle 310 and thegas storage 330. The gas supply line 320 is used to supply the processgas stored in the gas storage 330 to the gas supply nozzle 310. A valve321 is installed in the gas supply line 320. The valve 321 opens orcloses the gas supply line 320 and adjusts the flow rate of the processgas that is supplied through the gas supply line 320.

The plasma source 400 excites the process gas supplied into theprocessing space of the chamber 100 into plasma. An inductively coupledplasma (ICP) source may be used as the plasma source 400. The plasmasource 400 includes an antenna seal 410, an antenna 420, and a plasmapower supply 430. The antenna seal 410 has a cylindrical shape that isopen at the bottom. The antenna seal 410 has a space therein. Theantenna seal 410 has a diameter corresponding to that of the chamber100. A lower end of the antenna seal 410 is attachable to and detachablefrom the dielectric cover 120. The antenna 420 is disposed inside theantenna seal 410. The antenna 420 has a spiral coil shape wound aplurality of times and is connected to the plasma power supply 430. Theantenna 420 receives electric power from the plasma power supply 430.The plasma power supply 430 may be located outside the chamber 100. Theantenna 420, to which the electric power is applied, may form anelectromagnetic field in the processing space of the chamber 100. Theprocess gas is excited into plasma by the electromagnetic field.

The exhaust baffle 500 is located between the inner wall of the housing110 and the support unit 200. The exhaust baffle 500 has through-holes511 formed therein. The exhaust baffle 500 has an annular ring shape.The process gas supplied into the housing 110 passes through thethrough-holes 511 of the exhaust baffle 500 and is discharged throughthe exhaust hole 102. The flow of the process gas may be controlleddepending on the shape of the exhaust baffle 500 and the shape of thethrough-holes 511.

Hereinafter, the edge ring 240 and the impedance adjustment member 245of the substrate processing apparatus 10 according to an embodiment ofthe inventive concept will be described.

FIGS. 2 and 3 are enlarged views illustrating corrosion states caused byuse of the edge ring according to an embodiment of the inventiveconcept.

Referring to FIG. 2, the edge ring 240 has an initial thickness of T₀.The top side of the edge ring 240 is worn by a first thickness of T₁ byplasma generated from the process gas. Referring to FIG. 3, the edgering 240 is worn by a second thickness of T₂ by plasma.

As illustrated in FIGS. 2 and 3, the thickness of the edge ring 240 andthe shape of an upper surface thereof are changed due to the exposure toplasma. When the thickness and shape of the edge ring 240 are changed bythe corrosion, the thickness of a sheath on the top side of the edgering 240 is also changed according to the change in the thickness andshape of the edge ring 240. Hence, a tilting phenomenon may arise inwhich ions are obliquely incident on the edge of the substrate W and theresultant hole is formed to be obliquely inclined. The tiltingphenomenon may cause a reduction in yield. In an effort to manage thetilting phenomenon, a maintenance process may be added to recover theapparatus to the original state. However, substrates cannot be processedat all during the maintenance of the apparatus, which leads to reducedproductivity.

The temperature adjustment member 247 and a corrosion measurement member248 are connected to the controller 600.

The controller 600 controls the temperature adjustment member 247 toadjust the temperature of the impedance adjustment member 245. Forexample, the temperature adjustment member 247 may be a heater. Thecontroller 600 feeds back the temperature of the impedance adjustmentmember 245, based on temperature information received from the corrosionmeasurement member 248. The controller 600 may adjust the temperature ofthe impedance adjustment member 245 to a temperature at which a targetimpedance is able to be obtained, by controlling the temperatureadjustment member 247, based on the information received from thecorrosion measurement member 248.

The corrosion measurement member 248 may be a distance measurementsensor installed outside the impedance adjustment member 245. Thedistance measurement sensor may measure a amount of corrosion by amethod of measuring a change in the height of the impedance adjustmentmember 245. Although the corrosion measurement member 248 is illustratedas being installed outside the impedance adjustment member 245, thecorrosion measurement member 248 may be an electric field intensitymeasurement device or a temperature measurement device that is installedinside the impedance measurement member 245.

The amount of corrosion of the edge ring 240 represents the height ofthe edge ring 240 after corrosion relative to the initial heightthereof. The amount of corrosion of the edge ring 240 may be calculatedby various ways such as Equation 1: (the height of the edge ring 240after corrosion)/(the initial height of the edge ring 240), Equation 2:(the volume of the edge ring 240 after corrosion)/(the initial volume ofthe edge ring 240), Equation 3: (the intensity of an electric fieldafter corrosion)/(the intensity of an initial electric field), Equation4: (the height of the edge ring 240 after corrosion)−(the initial heightof the edge ring 240), Equation 5: (the volume of the edge ring 240after corrosion)−(the initial volume of the edge ring 240), Equation 6:(the intensity of an electric field after corrosion)−(the intensity ofan initial electric field), and the like.

The controller 600 may be connected with a memory 249. The memory 249has a amount of corrosion parameter input thereto. The amount ofcorrosion parameter may be an average amount of corrosion parameter ofthe edge ring 240 according to cumulative processing time or an averageamount of corrosion parameter of the edge ring 240 according to thenumber of substrates processed. The controller 600 adjusts thedielectric constant of the impedance adjustment member 245, based ondata received from the memory 249.

The corrosion measurement member 248 and the memory 249 are means forobtaining the amount of corrosion of the edge ring 240. Only one of themmay be provided, or both of them may be provided to complement eachother.

FIGS. 4 and 5 are enlarged views illustrating the behavior of plasmanear the edge ring of the support unit according to an embodiment of theinventive concept. In FIGS. 4 and 5, the intensity of an electric fieldis represented by the number of positive ions.

Referring to FIG. 4, the dielectric constant of the impedance adjustmentmember 245 varies according to temperature. Therefore, the intensity ofthe electric field may be increased by decreasing the dielectricconstant as illustrated in FIG. 4, or may be decreased by increasing thedielectric constant as illustrated in FIG. 5. Accordingly, the amount ofplasma incident on the edge of the substrate W may be maintained at apredetermined level by actively changing the intensity of the electricfield in response to a change in the thickness of the edge ring 240 andthe shape of the upper surface thereof due to exposure to the plasma.

For example, the dielectric constant of the impedance adjustment member245 may be controlled to increase with an increase in the amount ofcorrosion of the edge ring 240, and thus the amount of plasma incidenton the edge of the substrate W may be maintained at the predeterminedlevel.

FIG. 6 is a graph of dielectric constant versus temperature fordielectric substances according to an embodiment of the inventiveconcept.

Referring to FIG. 6, the graph depicts variations in dielectricconstants of first to fourth dielectric substances according totemperature. The variations in the dielectric constants according totemperature increase from the first dielectric substance to the fourthdielectric substance.

The first and second dielectric substances have the highest dielectricconstants at a temperature of T₁. The dielectric constants of the firstand second dielectric substances gradually decrease with a temperaturedrop in the temperature range below T₁ and gradually decrease with atemperature rise in the temperature range above T₁.

The third dielectric substance has the highest dielectric constant at atemperature of T₂. The temperature T₂ is higher than the temperature T₁.The dielectric constant of the third dielectric substance graduallydecreases with a temperature drop in the temperature range below T₂ andgradually decreases with a temperature rise in the temperature rangeabove T₂.

The fourth dielectric substance has the highest dielectric constant at atemperature of T₃. The temperature T₃ is higher than the temperature T₂.The dielectric constant of the fourth dielectric substance graduallydecreases with a temperature drop in the temperature range below T₃ andgradually decreases with a temperature rise in the temperature rangeabove T₃.

The first dielectric substance has a narrow variable impedance rangebecause the variation in the dielectric constant according totemperature is small, and the second to fourth dielectric substanceshave wide variable impedance ranges because the variations in thedielectric constants according to temperature are large.

The second dielectric substance is a dielectric substance containing 10wt % to 20 wt % of magnesium oxide (MgO), the third dielectric substanceis a dielectric substance containing 20 wt % to 35 wt % of magnesiumoxide (MgO), and the fourth dielectric substance is a dielectricsubstance containing 35 wt % to 50 wt % of magnesium oxide (MgO). Adielectric substance that has a large variation in dielectric constantaccording to temperature is also applicable, in addition to thedielectric substances containing magnesium oxide.

FIG. 7 is a graph of dielectric constant versus temperature for thefourth dielectric substance according to an embodiment of the inventiveconcept.

Referring to FIG. 7, the fourth dielectric substance has the highestdielectric constant at the temperature of T₃. If a specific process isperformed at a first process temperature, the temperature of thetemperature adjustment member 247 is raised (direction a) to increasethe dielectric constant and is lowered (direction b) to decrease thedielectric constant.

If a specific process is performed at a second process temperature, thetemperature of the temperature adjustment member 247 is lowered(direction c) to increase the dielectric constant and is raised(direction d) to decrease the dielectric constant.

According to the embodiments of the inventive concept, the substrateprocessing apparatus and method may improve substrate processingefficiency in processing a substrate using plasma.

In addition, according to the embodiments of the inventive concept, thesubstrate processing apparatus and method may uniformly controldistribution of plasma incident on a substrate.

While the inventive concept has been described with reference toexemplary embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the spirit and scope of the inventive concept. Therefore, it shouldbe understood that the above embodiments are not limiting, butillustrative.

What is claimed is:
 1. An apparatus for processing a substrate, theapparatus comprising: a process chamber having a processing spaceinside; a support unit configured to support the substrate in theprocessing space; a gas supply unit configured to supply a process gasinto the processing space; and a plasma source configured to generateplasma from the process gas, wherein the support unit comprises: asupport on which the substrate is placed; an edge ring configured tosurround the substrate placed on the support; an impedance adjustmentmember provided below the edge ring; and a temperature adjustment memberconfigured to variably adjust temperature of the impedance adjustmentmember.
 2. The apparatus of claim 1, wherein the impedance adjustmentmember is made of a material, the dielectric constant of which variesaccording to temperature.
 3. The apparatus of claim 2, furthercomprising: a controller configured to control the temperatureadjustment member, wherein the controller controls the temperatureadjustment member to change the dielectric constant of the impedanceadjustment member as a amount of corrosion of the edge ring increases.4. The apparatus of claim 3, wherein the controller controls thetemperature adjustment member to increase the dielectric constant of theimpedance adjustment member as the amount of corrosion of the edge ringincreases.
 5. The apparatus of claim 3, wherein the apparatus furthercomprises a corrosion measurement member configured to measure theamount of corrosion of the edge ring, and wherein the controllerreceives the amount of corrosion measured by the corrosion measurementmember.
 6. The apparatus of claim 1, wherein the impedance adjustmentmember is formed of a dielectric substance containing magnesium oxide.7. The apparatus of claim 6, wherein the dielectric substance contains10 wt % to 50 wt % of magnesium oxide.
 8. The apparatus of claim 1,further comprising: a controller configured to control the temperatureadjustment member, wherein the controller controls temperature of thetemperature adjustment member, based on a amount of corrosion of theedge ring.
 9. The apparatus of claim 1, wherein the impedance adjustmentmember has the highest dielectric constant at a first temperature, anincreasing dielectric constant with a temperature rise in a range belowthe first temperature, and a decreasing dielectric constant with atemperature rise in a range above the first temperature, and wherein thecontroller controls the temperature adjustment member to raise thetemperature of the impedance adjustment member in the range below thefirst temperature and lower the temperature of the impedance adjustmentmember in the range above the first temperature, when a amount ofcorrosion of the edge ring increases.
 10. The apparatus of claim 1,wherein the impedance adjustment member has a ring shape with an uppersurface that corresponds to a shape of a lower portion of the edge ring.11. A method for processing a substrate, the method comprising:processing the substrate by supplying plasma onto the substrate placedon a support; and controlling a plasma density above an edge ring byadjusting a dielectric constant of an impedance adjustment member placedbelow the edge ring, the edge ring being configured to surround a sideof the substrate placed on the support.
 12. The method of claim 11,further comprising: variably adjusting the dielectric constant of theimpedance adjustment member, based on a amount of corrosion of the edgering.
 13. The method of claim 11, wherein the impedance adjustmentmember is formed of a dielectric substance containing magnesium oxide.14. The method of claim 13, wherein the dielectric substance contains 10wt % to 50 wt % of magnesium oxide.
 15. The method of claim 11, furthercomprising: controlling temperature to increase the dielectric constantof the impedance adjustment member as a amount of corrosion of the edgering increases.
 16. The method of claim 11, wherein the impedanceadjustment member has the highest dielectric constant at a firsttemperature, an increasing dielectric constant with a temperature risein a range below the first temperature, and a decreasing dielectricconstant with a temperature rise in a range above the first temperature,and wherein temperature of the impedance adjustment member is raised inthe range below the first temperature and lowered in the range above thefirst temperature when a amount of corrosion of the edge ring increases.17. The method of claim 11, further comprising: measuring a amount ofcorrosion of the edge ring; and changing the dielectric constant of theimpedance adjustment member according to the measured amount ofcorrosion.
 18. The method of claim 11, further comprising: changing thedielectric constant of the impedance adjustment member according tocumulative substrate processing time.
 19. The method of claim 11,further comprising: changing the dielectric constant of the impedanceadjustment member according to the number of substrates processed.